<!DOCTYPE html>
<html>
<head>
	<style>
	p { margin: 20px 0 0 }
	b { color: blue; }
</style>
	<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
<input id="check1" type="checkbox" checked="checked">
<label for="check1">Check me</label>
<p></p>
<script>
	$("input").change(function() {
	var $input = $(this);
	$("p").html(".attr('checked'): <b>" + $input.attr('checked') + "</b><br>"
				+ ".prop('checked'): <b>" + $input.prop('checked') + "</b><br>"
				+ ".is(':checked'): <b>" + $input.is(':checked') ) + "</b>";
}).change();
</script>
</body>
</html>